.header{
    width: 100%;
    height: 50px;
    background-color: rgb(230, 230, 230);
    box-shadow: 0 0 10px silver;
    position: fixed;
    top: 0;
    left: 0;
    border-bottom: 1px solid silver;
    border-radius: 5px;
}
.header > div{
    margin: 0 auto;
    width: 1200px;
    height: 100%;
    display: flex;
    justify-content: space-evenly;
    align-items: center;
    position: relative;
}
.header > div::before{
    display: table;
    clear: both;
    content: '';
}
.header .search{
    width: 280px;
    height: 40px;
    margin-top: 8px;
    position: absolute;
    left: 0;
}

.header .newslist{
    width: 280px;
    height: 26px;
    list-style: none;
    position: absolute;
    left: 50%;
    top: 12px;
    margin-left: -140px;
    overflow: hidden;
}
.header .newslist ul{
    padding: 0;
    margin: 0;
    position: relative;
    top: 0px;
    animation: moveUp 10s linear infinite;
}

@keyframes moveUp{
    20%{
        top: 0px;
    }
    33%{
        top: -26px;
    }
    
    53%{
        top: -26px;
    }
    66%{
        top: -52px;
    }
    86%{
        top: -52px;
    }
    86.1%{
        top: 0px;
    }
}

.header ul li{
    list-style: none;
    width: 100%;
    height: 26px;
    text-align: center;
    line-height: 26px;
    font-size: 20px;
    font-weight: bold;
    /* 超过容器大小，显示 ... */
    overflow: hidden;
    text-overflow: ellipsis;
}

.header .useroption{
    width: 280px;
    text-align: right;
    position: absolute;
    right: 0;
}